HO & O - High Quality Scale Modeling Architecture and Railroading

We begin using the foam core by cutting strips as wide as the height of the exterior walls.
Start with one edge of the sheet and cut strips using a metal straight edge and hobby knife. This cut is

going to be the top or bottom edge of a wall, so it should be as close to ninety degrees as possible.

If you have a steady hand and good eye, the hobby knife and metal straight edge is all you need.

Be very careful your fingers don't extend over the edge of the metal ruler even slightly!